Day: April 16, 2024

#Shock

Hypovolemic Shock

By Dr. Ahmed Hafez

Background Hypovolemic shock refers to a medical or surgical condition in which rapid fluid loss results in multiple organ failure due to inadequate circulating volume and subsequent inadequate perfusion. Endothelium plays a critical role in vascular physiological, pathophysiological, and reparative processes. The functions of the endothelium are highly altered following hypovolemic shock due to ischemia of the endothelial cells and by reperfusion due to resuscitation with fluids. Due to oxygen deprivation, endothelial cell apoptosis is induced following hypovolemic shock.  Most often, hypovolemic shock is secondary to rapid blood loss (hemorrhagic shock). Acute external blood loss secondary to penetrating trauma and

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#Coma

Hypoglycemic coma

By Dr. Ahmed Hafez

Practice Essentials Hypoglycemia is characterized by a reduction in plasma glucose concentration to a level that may induce symptoms or signs such as altered mental status and/or sympathetic nervous system stimulation. This condition typically arises from abnormalities in the mechanisms involved in glucose homeostasis. The most common cause of hypoglycemia in patients with diabetes is injecting a shot of insulin and skipping a meal or overdosing insulin.  The image below depicts a diagnostic algorithm for hypoglycemia. Signs and symptoms of hypoglycemia The glucose level at which an individual becomes symptomatic is highly variable (threshold generally at < 50 mg/dL). Carefully

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#Coma

Metabolic Acidosis Coma

By Dr. Ahmed Hafez

Practice Essentials Metabolic acidosis is a clinical disturbance characterized by an increase in plasma acidity. Metabolic acidosis should be considered a sign of an underlying disease process. Identification of this underlying condition is essential to initiate appropriate therapy.  The initial therapeutic goal for patients with severe acidemia is to raise the systemic pH above 7.1-7.2, a level at which dysrhythmias become less likely and cardiac contractility and responsiveness to catecholamines will be restored. This article discusses the differential diagnosis of metabolic acidosis and presents a scheme for identifying the underlying cause of acidosis by using laboratory tests that are available

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#Coma

Hyperosmolar Hyperglycemic State HHS Coma

By Dr. Ahmed Hafez

Hyperosmolar hyperglycemic state is a life-threatening emergency manifested by marked elevation of blood glucose and hyperosmolarity with little or no ketosis. Although there are multiple precipitating causes, underlying infections are the most common. Other causes include certain medications, nonadherence to therapy, undiagnosed diabetes mellitus, substance abuse, and coexisting disease. In children and adolescents, hyperosmolar hyperglycemic state is often present when type 2 diabetes is diagnosed. Physical findings include profound dehydration and neurologic symptoms ranging from lethargy to coma. Treatment begins with intensive monitoring of the patient and laboratory values, especially glucose, sodium, and potassium levels. Vigorous correction of dehydration is

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#Coma

Diabetic Ketoacidosis (DKA) coma

By Dr. Ahmed Hafez

Practice Essentials Diabetic ketoacidosis (DKA) is an acute, major, life-threatening complication of diabetes characterized by hyperglycemia, ketoacidosis, and ketonuria. It occurs when absolute or relative insulin deficiency inhibits the ability of glucose to enter cells for utilization as metabolic fuel, the result being that the liver rapidly breaks down fat into ketones to employ as a fuel source. The overproduction of ketones ensues, causing them to accumulate in the blood and urine and turn the blood acidic. DKA occurs mainly in patients with type 1 diabetes, but it is not uncommon in some patients with type 2 diabetes. Laboratory studies

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#Coma

Cerebral coma

By Dr. Ahmed Hafez

What Is a Coma? A coma is a prolonged state of unconsciousness. During a coma, a person is unresponsive to their environment. The person is alive and looks like they are sleeping. However, unlike in a deep sleep, the person cannot be awakened by any stimulation, including pain. A coma is a prolonged state of unconsciousness. It is caused by an injury to the brain that can be due to increased pressure, bleeding, loss of oxygen, or buildup of toxins. The injury can be temporary and reversible but can also be permanent and lead to death. Coma Causes A coma

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#Statistics

Study designs

By Sama Mohamed

Overview The reporting of medical findings originally focussed on the description of individual patients with an unusual presentation. This would be a novel or rarely used method of treatment, or an unexpected outcome. Some reports described several such cases treated by the same practitioner. The 20th century saw the development of larger scale studies that involved (for example) the collection of the views of individual patients, the inspection of patient medical records, following patients over time using standardised record keeping, or performing comparisons of patients receiving different treatments. Recent years have seen the development of medical literature databases on the Internet, facilitating

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#Statistics

Sampling

By Sama Mohamed

Rationale for sampling A population is a complete group of individuals such as all the residents of a country. Involving the whole population is unrealistic in terms of cost and staff time. Sampling is preferable and often the only way forward. Individuals who are reasonably easy to contact are selected making the study viable. Remember that due to random fluctuation information gained from different samples will not be identical even with the same method of selection. Also, some of the individuals selected will not be willing and/ or able to be involved leading to non-response bias. Random sampling A sampling

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#Statistics

Hypothesis testing

By Sama Mohamed

Investigating a population Deductions about the characteristics of a population can be made using a representative sample drawn from the population. This procedure starts with a statement regarding the population and information from the sample is used to decide whether or not there is enough evidence to conclude that this statement might be false. The null hypothesis The initial statement about the population (the null hypothesis) is very specific. For the case of a single sample it needs to describe the population, introduce the characteristic under study, include a statistical measure of interest (e.g. the mean) and propose an assumed value for this measure.

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#Statistics

Diagnostic tests

By Sama Mohamed

Introduction Diagnostic testing is based on the phenomenon that components of blood and other body fluids are found at different concentrations in individuals with a particular disease relative to people without the disease. For instance, fasting blood glucose concentrations are raised in those who suffer from diabetes. Blood glucose concentration can therefore be used as a method for identifying undetected cases of diabetes in the population. In men, prostate specific antigen (PSA) levels in blood are higher on average in those who have prostate cancer and can be used to detect and manage progression of the disease. In these notes,

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#Statistics

Data presentation

By Sama Mohamed

Summary Data can be binary, nominal, ordered, discrete quantitative, or continuous quantitative. Graphs include bar-charts, pie-charts, histograms, box-and-whisker plots and scatter diagrams. The type of graph used should be chosen according to the type of data being displayed. Be aware that graphs may be presented in misleading ways. Furthermore, graphs can be symmetrical, positively skewed or negatively skewed. Types of average include the mean, median, and mode. Measures of spread include the range, interquartile range, variance, and standard deviation. Means and measures of spread should be chosen according to the type of data being summarised and some measures are susceptible

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#Pharmacology

Statins

By Sama Mohamed

Introduction Statins have revolutionised the management of hypercholesterolaemia. Statins have become essential in the management of patients with, or at risk, of cardiovascular disease including coronary artery disease (CAD), cerebrovascular disease and peripheral vascular disease (PVD). Indications Statins were primarily created to treat hypercholesterolaemia, which is an independent risk factor for cardiovascular disease. Statins are indicated in both primary and secondary prevention of cardiovascular disease for many conditions. Primary prevention Cardiovascular risk assessment score ≥10%* and ≤ 84 years old (risk/benefit if >84) Cardiovascular risk assessment score ≥10%* and type 2 diabetes mellitus (T2DM) Type 1 diabetes mellitus (T1DM) and additional criteria (age, kidney disease, duration) Chronic kidney disease (CKD)

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#Pharmacology

Oxygen

By Sama Mohamed

Overview Oxygen should be regarded as a drug that is prescribed for patients with hypoxaemia (low blood oxygen concentration). Oxygen is the most commonly used drug in emergency situations. It can be a life-saving drug to prevent severe hypoxaemia that refers to a low arterial oxygen concentration. However, used inappropriately oxygen can have serious or fatal consequences. The headline point is that oxygen should be used to treat hypoxaemia and maintain a patients’ saturations in the target range. This should be 94-98% or 88-92% in patients at risk of type 2 respiratory failure. When prescribing and administering oxygen there are several

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#Pharmacology

Metformin

By Sama Mohamed

Summary Metformin is considered the first-line hypoglycaemic agent for the treatment of type 2 diabetes mellitus. Metformin has been one of most prescribed medications worldwide over the last decade. The typical starting dose for adults is 500 mg daily, which can be increased to a maximum dose of 2 g daily. The most common adverse-effect is gastrointestinal upset (i.e. nausea, abdominal pain, diarrhoea), although rarely metformin can result in lactic acidosis. Origin Derived from galegine, which is a natural protein found in the plant Galega officinalis. Metformin was first synthesised around the 1920s and then used clinically in the 1950s. It is now

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#Pharmacology

Bronchodilators

By Sama Mohamed

Introduction Airway resistance occurs as frictional forces oppose the flow of air through the conducting airways. Normal flow is laminar, the flow is ordered and quicker in the centre. As airways divide and become narrow increasingly turbulent flow occurs. Poiseuille’s equation describes resistance (if flow is laminar) with resistance (R), length (L), radius (r) and viscosity (η). π and 8 are constants: Resistance (R) = 8 x L x η / π x r4 Bronchomotor tone Bronchomotor tone controls the ease with which air is conducted through airways. It exhibits a circadian rhythm where tone is greatest in the early morning. We note from the

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#Pharmacology

Antihypertensives

By Sama Mohamed

Overview The anti-hypertensives are an important & broad group of medications. Hypertension is a very common condition that represents a significant source of morbidity and mortality. It is a major risk factor for MI, stroke and chronic kidney disease. Hypertension is managed in a step-wise fashion according to the NICE guidelines (see our Hypertension notes for more). Several groups of drugs, by varying mechanisms, are used to reduce blood pressure. Regulation Blood pressure is maintained by a number of physiological reflexes that respond to acute and chronic changes. Blood pressure = cardiac output x peripheral vascular resistance Numerous interconnected systems contribute to the regulation of blood pressure.

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#Pharmacology

Antiarrhythmics

By Sama Mohamed

Vaughan-William’s classification Anti-arrhythmics are drugs that modify cardiac conduction, they are used to treat arrhythmias and are classified according to the Vaughan-William’s system. This classification divides these drugs into four classes according to their effects on cardiac action potential. Anti-arrhythmics have complex actions and classes may overlap. It is important to note, that this classification system has become increasingly inadequate with improved understandings of drug mechanisms and development of new antiarrhythmics. Arrhythmogenesis To understand the action of the antiarrhythmics it helps to understand how arrhythmias may develop. Arrhythmias are disorders of rate and rhythm of the heart, which arise due to either abnormal generation or

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#Histories

Pleural fluid

By Sama Mohamed

Overview Analysis of pleural fluid is important for the workup of a pleural effusion. A pleural effusion is the most common manifestation of pleural disease and it may occur from a wide range of aetiologies. It refers to an abnormal collection of fluid with the pleural space. Pleural fluid may be aspirated and analysed to help determine the underlying cause. Pleural effusions may be a manifestation of numerous conditions that requires a careful history, clinical examination, imaging (e.g. chest x-ray), and pleural fluid analysis to determine the cause. Sometimes the cause may be obvious (e.g. heart failure) and pleural aspiration is

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#Pathology

Blood bottles

By Sama Mohamed

Overview We give a practical guide to the use of blood bottles in clinical practice. In modern medicine, most hospitals and GP practices are set up with computer software that automatically prints blood labels following a request. This process automatically assigns a test to a blood bottle and reduces the need to handwrite patient information. The required blood bottle on these labels is differentiated by the coloured top (e.g. lavender or gold). Occasionally, when the test is specialist or there is ‘computer downtime’ knowledge of the appropriate blood bottle is required, but you can always ask! We outline a practical guide to

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#Shock

Cardiogenic shock

By Dr. Ahmed Hafez

Cardiogenic shock is a medical emergency resulting from inadequate blood flow to the body’s organs due to the dysfunction of the heart. Signs of inadequate blood flow include low urine production (<30 mL/hour), cool arms and legs, and decreased level of consciousness. People may also have a severely low blood pressure and heart rate. Causes of cardiogenic shock include cardiomyopathic, arrhythmic, and mechanical. Cardiogenic shock is most commonly precipitated by a heart attack. Treatment of cardiogenic shock depends on the cause with the initial goals to improve blood flow to the body. If cardiogenic shock is due to a heart

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#Pathology

Ascitic fluid

By Sama Mohamed

Overview Ascites refers to the presence of pathological fluid within the abdominal cavity. In men, no fluid should be present. In women, up to 20 mls may be considered normal depending on the timing of their menstrual cycle. Ascites is most commonly associated with liver disease. In this context, ascites develops due to portal hypertension. This refers to increased pressure within the portal venous system that drains blood from the gastrointestinal tract to the liver. Other causes of ascites are broadly due to local infiltration (e.g. tumour) of the peritoneal lining, inflammation or infection. Aetiology Ascites can be broadly be divided

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#Histories

Respiratory history

By Sama Mohamed

Introduction The respiratory history should focus on key system-specific symptoms related to the respiratory system. A respiratory history focuses the consultation on the respiratory system. This is usually because a patient presents with a respiratory problem such as shortness of breath or wheeze. The idea of a system-specific history is to explore key factors that are relevant to the affected system during the consultation. In respiratory disease, this may include pertinent past medical history (e.g. asthma/COPD), inhaler use, smoking history, occupational exposures, and even childhood illnesses. History of presenting complaint Breathlessness is a major symptom of respiratory disease. Shortness of breath or

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#Histories

Musculoskeletal history

By Sama Mohamed

Overview Musculoskeletal disorders are often multi-system that requires a wide range of questioning in the history. A musculoskeletal (MSK) history focuses primarily on presentations affecting the musculoskeletal system including bones, joints, tendons, ligaments, and muscles. Remember that many musculoskeletal disorders are multi-system meaning a wide range of inquiry is required during the consultation to determine the involvement of other organ systems. Presentations may be acute and obvious (e.g. fractured bone after fall) or more chronic with vague extending over months to years. Be patient and listen to the patient. Finally, it is essential to ask what the functional and psychological impact of

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#Histories

Gastrointestinal history

By Sama Mohamed

Overview The gastrointestinal (GI) history should focus on key system-specific symptoms related to the GI tract. The gastrointestinal tract runs all the way from mouth to anus. Pathology can occur anywhere along the tract from oesophagus to the intestines to the bile ducts. Therefore, the GI history is a system-specific history that needs to focus on the different elements that can affect each part. Any GI history should focus on the presenting symptom of the patient (e.g. diarrhoea or dysphagia) and then proceed to ask more broad questions related to other parts of the GI tract History of presenting complaint Isolate

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